Doug has been doing some excellent work on Annozilla, and there is an
experimental version available. This brings a lot of new functionality to
Annozilla (including multiple server support). This version will form the
basis of Annozilla 0.4.

This is the the Annozilla project, designed to view and
create annotations associated with a web page, as defined by the W3C Annotea project. The idea is to
store annotations as RDF on a server, using XPointer (or at least XPointer-like
constructs) to identify the region of the document being annotated.

The intention of Annozilla is to use Mozilla's native facilities to
manipulate annotation data - its built-in RDF handling to parse the
annotations, and nsIXmlHttpRequest to submit data when creating
annotations.